A simple hydrothermal route has been developed for the fabricating Zn O hierarchical micro/nanostructure with excellent reproducibility. SEM and TEM analysis show that the hierarchical rod is a single-crystal, suggest...A simple hydrothermal route has been developed for the fabricating Zn O hierarchical micro/nanostructure with excellent reproducibility. SEM and TEM analysis show that the hierarchical rod is a single-crystal, suggesting that many single-crystal micro/nanorods are assembled into Zn O hierarchical micro/nanostructures. The morphologies of the hierarchical rods can be conveniently tailored by changing the reaction parameters. And we also found citric acid plays a crucial role in the formation process of Zn O micro/nanostructures. Room-temperature photoluminescence spectra reveals that the Zn O hierarchical micro/nanostructures have a strong emission peak at 440 nm and several weak emission peaks at 420, 471 and541 nm, respectively.展开更多
Optoelectronic characterisation of an individual ZnO nanowire in contact with a micro-grid template has been studied. The low-cost micro-grid template made by photolithography is used to fabricate the ohmic contact me...Optoelectronic characterisation of an individual ZnO nanowire in contact with a micro-grid template has been studied. The low-cost micro-grid template made by photolithography is used to fabricate the ohmic contact metal electrodes. The current increases linearly with the bias, indicating good ohmic contacts between the nanowire and the electrodes. The resistivity of the ZnO nanowire is calculated to be 3.8 Ω·cm. We investigate the photoresponses of an individual ZnO nanowire under different light illumination using light emitting diodes （λ= 505 nm, 460 nm, 375 nm） as excitation sources in atmosphere. When individual ZnO nanowire is exposured to different light irradiation, we find that it is extremely sensitive to UV illumination; the conductance is much larger upon UV illumination than that in the dark at room temperature. This phenomenon may be related to the surface oxygen molecule adsorbtion, which indicates their potential application to the optoelectronic switching device.展开更多
ZnO micro/nano complex structure films, including reticulate papillary nodes, petal-like and flake-hole, have been self-assembled by a hydrothermal technique at different temperatures without metal catalysts. The wett...ZnO micro/nano complex structure films, including reticulate papillary nodes, petal-like and flake-hole, have been self-assembled by a hydrothermal technique at different temperatures without metal catalysts. The wettability of the above film surfaces was modified with a simple coating of heptadecafluorodecyltrimethoxy-silane in toluene. After modifying, the surface of ZnO film grown at 50℃ was converted from superhydrophilic with a water contact angle lower than 5° to superhydrophobic with a water contact angle of 165° Additionally, the surface of reticulate papillary nodes ZnO film grown at 100 ℃ had excellent superhydrophobicity, with a water contact angle of 173° and a sliding angle lower than 2° Furthermore, the water contact angle on the surface of petal-like and flake-hole ZnO films grown at 150℃ and 200℃ were found to be 140° and 120°, respectively. The wettability for the samples was found to depend strongly on the surface morphology which results from the growth temperature.展开更多
This paper reports that the film composed of flower-like ZnO micro-spheres, which consists of nano-sheets, is fab- ricated by chemical bath deposition. By adding hydrogen fluoride （HF） into the reaction solution, wh...This paper reports that the film composed of flower-like ZnO micro-spheres, which consists of nano-sheets, is fab- ricated by chemical bath deposition. By adding hydrogen fluoride （HF） into the reaction solution, which contains zinc nitrate hexahydrate and hexamethylenetetramine, the ZnO crystal growth process is changed and the film composed by ZnO micro-spheres is obtained after keeping the reaction solution at 95 ℃ for 2 h. The morphology, crystal phase and wettahility of the sample axe characterized by scanning electron microscope, x-ray diffraction and contact angle meter, respectively. The results show that the filrrl has the micro-nano compound structure. After modification with heptadecafluorodecyltrimethoxy-silane, the wettability of the film changed from superhydrophilicity to superhydropho-bicity, on which water contact angle and the sliding angle are 154° and less than 5° for 8-μL water droplet, respectively. Additionally, the formation mechanism of the ZnO micro-sphere is also discussed.展开更多
The hydrophobicity of the lotus leaf is mainly due to its surface micro-nano composite structure. In order to mimic the lotus structure, ZnO micro-nano composite hydrophobic films were prepared via the three-step meth...The hydrophobicity of the lotus leaf is mainly due to its surface micro-nano composite structure. In order to mimic the lotus structure, ZnO micro-nano composite hydrophobic films were prepared via the three-step method. On thin buffer films of SiO2, which were first fabricated on glass substrates by the so,gel dip-coating method, a ZnO seed layer was deposited via RF magnetron sputtering. Then two different ZnO films, micro-nano and micro-only flowerlike structures, were grown by the hydrothermal method. The prepared films have different hydrophobic properties after surface modification. The structures of the obtained ZnO films were characterized using x-ray diffraction and field-emission scanning electron microscopy. A conclusion that a micro-nano composite structure is more beneficial to hydrophobicity than a micro-only structure was obtained through research into the effect of structure on hydrophobic properties.展开更多
ZnO micro-nano spheres covered with ZnO nanowires were synthesized at 650 ℃ without using cataly-sts. Characterizations of the products by TEM, SEM, XRD, SAED and EDS showed that the ZnO nanowires were of high purity...ZnO micro-nano spheres covered with ZnO nanowires were synthesized at 650 ℃ without using cataly-sts. Characterizations of the products by TEM, SEM, XRD, SAED and EDS showed that the ZnO nanowires were of high purity and single-crystalline with hexagonal wurtzite structure. The diameter of ZnO nanowires ranges from 60 to 200 nm and the length is longer than 10 μm. The size of the ZnO micro-nano spheres ranges from hundreds of nanometers to tens of microns. At the same time, the growth mechanism of ZnO micro-nano spheres is discussed.展开更多
基金supported by the Program for the Science and Technology Commission of Shanghai Municipality (No. 0952nm02500)
文摘A simple hydrothermal route has been developed for the fabricating Zn O hierarchical micro/nanostructure with excellent reproducibility. SEM and TEM analysis show that the hierarchical rod is a single-crystal, suggesting that many single-crystal micro/nanorods are assembled into Zn O hierarchical micro/nanostructures. The morphologies of the hierarchical rods can be conveniently tailored by changing the reaction parameters. And we also found citric acid plays a crucial role in the formation process of Zn O micro/nanostructures. Room-temperature photoluminescence spectra reveals that the Zn O hierarchical micro/nanostructures have a strong emission peak at 440 nm and several weak emission peaks at 420, 471 and541 nm, respectively.
基金supported by the National Natural Science Foundation of China (Grant Nso. 60776010,60940021 and 11074060)the Natural Science Foundation of Heilongjiang Province,China (Grant No. A2008-07)the Doctoral Start-up Fund of Harbin Normal University,China
文摘Optoelectronic characterisation of an individual ZnO nanowire in contact with a micro-grid template has been studied. The low-cost micro-grid template made by photolithography is used to fabricate the ohmic contact metal electrodes. The current increases linearly with the bias, indicating good ohmic contacts between the nanowire and the electrodes. The resistivity of the ZnO nanowire is calculated to be 3.8 Ω·cm. We investigate the photoresponses of an individual ZnO nanowire under different light illumination using light emitting diodes （λ= 505 nm, 460 nm, 375 nm） as excitation sources in atmosphere. When individual ZnO nanowire is exposured to different light irradiation, we find that it is extremely sensitive to UV illumination; the conductance is much larger upon UV illumination than that in the dark at room temperature. This phenomenon may be related to the surface oxygen molecule adsorbtion, which indicates their potential application to the optoelectronic switching device.
基金Project supported by the 973 Program of China (Grant No. 2006CB302900)National Natural Science Foundation of China(Grant No. 50872129)
文摘ZnO micro/nano complex structure films, including reticulate papillary nodes, petal-like and flake-hole, have been self-assembled by a hydrothermal technique at different temperatures without metal catalysts. The wettability of the above film surfaces was modified with a simple coating of heptadecafluorodecyltrimethoxy-silane in toluene. After modifying, the surface of ZnO film grown at 50℃ was converted from superhydrophilic with a water contact angle lower than 5° to superhydrophobic with a water contact angle of 165° Additionally, the surface of reticulate papillary nodes ZnO film grown at 100 ℃ had excellent superhydrophobicity, with a water contact angle of 173° and a sliding angle lower than 2° Furthermore, the water contact angle on the surface of petal-like and flake-hole ZnO films grown at 150℃ and 200℃ were found to be 140° and 120°, respectively. The wettability for the samples was found to depend strongly on the surface morphology which results from the growth temperature.
基金Project supported by the National Natural Science Foundation of China (Grant No. 50872129)Natural Science Foundation of Anhui Province of China (Grant No. 070414187)
文摘This paper reports that the film composed of flower-like ZnO micro-spheres, which consists of nano-sheets, is fab- ricated by chemical bath deposition. By adding hydrogen fluoride （HF） into the reaction solution, which contains zinc nitrate hexahydrate and hexamethylenetetramine, the ZnO crystal growth process is changed and the film composed by ZnO micro-spheres is obtained after keeping the reaction solution at 95 ℃ for 2 h. The morphology, crystal phase and wettahility of the sample axe characterized by scanning electron microscope, x-ray diffraction and contact angle meter, respectively. The results show that the filrrl has the micro-nano compound structure. After modification with heptadecafluorodecyltrimethoxy-silane, the wettability of the film changed from superhydrophilicity to superhydropho-bicity, on which water contact angle and the sliding angle are 154° and less than 5° for 8-μL water droplet, respectively. Additionally, the formation mechanism of the ZnO micro-sphere is also discussed.
基金supported by the Science Fund of Anhui Province,China(Grant No 070414187)the National Fund for Fostering Talents in Basic Science of China(Grant No J0630319/J0103)
文摘The hydrophobicity of the lotus leaf is mainly due to its surface micro-nano composite structure. In order to mimic the lotus structure, ZnO micro-nano composite hydrophobic films were prepared via the three-step method. On thin buffer films of SiO2, which were first fabricated on glass substrates by the so,gel dip-coating method, a ZnO seed layer was deposited via RF magnetron sputtering. Then two different ZnO films, micro-nano and micro-only flowerlike structures, were grown by the hydrothermal method. The prepared films have different hydrophobic properties after surface modification. The structures of the obtained ZnO films were characterized using x-ray diffraction and field-emission scanning electron microscopy. A conclusion that a micro-nano composite structure is more beneficial to hydrophobicity than a micro-only structure was obtained through research into the effect of structure on hydrophobic properties.
文摘ZnO micro-nano spheres covered with ZnO nanowires were synthesized at 650 ℃ without using cataly-sts. Characterizations of the products by TEM, SEM, XRD, SAED and EDS showed that the ZnO nanowires were of high purity and single-crystalline with hexagonal wurtzite structure. The diameter of ZnO nanowires ranges from 60 to 200 nm and the length is longer than 10 μm. The size of the ZnO micro-nano spheres ranges from hundreds of nanometers to tens of microns. At the same time, the growth mechanism of ZnO micro-nano spheres is discussed.
